초록 ▼

A preferred embodiment of the invention is a parking permit, while other preferred embodiments include transit tickets, admission tickets, time passage indicators for other applications. Also within the scope of this invention are patterned indicators printed with inks having multiple sensitivities

A preferred embodiment of the invention is a parking permit, while other preferred embodiments include transit tickets, admission tickets, time passage indicators for other applications. Also within the scope of this invention are patterned indicators printed with inks having multiple sensitivities for indicating tampering with goods in packages sealed with such indicators.

대표청구항 ▼

[ We claim:] [1.] An indicator comprising:a first substrate having first and second surfaces;an ink pattern on said first surface of said first substrate;a second substrate having first and second surfaces;a chemical agent on the first surface of the second substrate;wherein the first surfaces of ea

[ We claim:] [1.] An indicator comprising:a first substrate having first and second surfaces;an ink pattern on said first surface of said first substrate;a second substrate having first and second surfaces;a chemical agent on the first surface of the second substrate;wherein the first surfaces of each substrate overlay and are in contact with each other, the chemical agent and the ink pattern coacting to cause the ink pattern to bleed along the first surface of the first substrate to cause a visually perceptible change in the pattern over a selected time interval.